Band structure engineering via piezoelectric fields in strained anisotropic CdSe/CdS nanocrystals.

Autor: Christodoulou S; 1] Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy [2] Department of Physics, University of Genoa, via Dodecaneso 33, IT-16146 Genova, Italy., Rajadell F; Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain., Casu A; Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy., Vaccaro G; Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy., Grim JQ; Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy., Genovese A; Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy., Manna L; Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy., Climente JI; Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain., Meinardi F; Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy., Rainò G; IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland., Stöferle T; IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland., Mahrt RF; IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland., Planelles J; Departament de Quimica Fisica i Analitica, Universitat Jaume I, ES-12080 Castellón, Spain., Brovelli S; Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, IT-20125 Milano, Italy., Moreels I; Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2015 Jul 29; Vol. 6, pp. 7905. Date of Electronic Publication: 2015 Jul 29.
DOI: 10.1038/ncomms8905
Abstrakt: Strain in colloidal heteronanocrystals with non-centrosymmetric lattices presents a unique opportunity for controlling optoelectronic properties and adds a new degree of freedom to existing wavefunction engineering and doping paradigms. We synthesized wurtzite CdSe nanorods embedded in a thick CdS shell, hereby exploiting the large lattice mismatch between the two domains to generate a compressive strain of the CdSe core and a strong piezoelectric potential along its c-axis. Efficient charge separation results in an indirect ground-state transition with a lifetime of several microseconds, almost one order of magnitude longer than any other CdSe/CdS nanocrystal. Higher excited states recombine radiatively in the nanosecond time range, due to increasingly overlapping excited-state orbitals. k˙p calculations confirm the importance of the anisotropic shape and crystal structure in the buildup of the piezoelectric potential. Strain engineering thus presents an efficient approach to highly tunable single- and multiexciton interactions, driven by a dedicated core/shell nanocrystal design.
Databáze: MEDLINE
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